This blog provides updated forecasts and comments on current weather or other topics

Tuesday, November 8, 2011

Bering Superstorm

An extraordinarily intense storm is now churning through the Bering Sea.

The central pressure is roughly 945 hPa--similar to a category three hurricane, and in fact this storm does have hurricane-force winds. (a hPa is the same as a millibar, mb, which you may be more familiar with. In the inches of mercury units this would be 27.9 inches). Take a look at a recent National Weather Surface surface analysis (for 4 PM Tuesday). 943 hPa low center and the NWS folks note the hurricane-force winds (sustained winds of 64 kt or more). That is a lot of isobars, with extraordinary pressure gradients.

It is quite unusual to have a storm this strong so far north. This storm developed very rapidly--approximately 60 hPa in 48 h, thus putting it in the category of explosive deepeners or "meteorological bombs" as known in the weather literature. Here is an image of the storm from of the polar orbiter weather satellites...the low center is in the middle of the swirl.

This storm is far deeper and stronger than the famous "Perfect Storm" of movie fame--at its most intense that low only got down to 972 hPa...nearly 30 hPa higher pressure. The has passed near a few weather buoys. Here are a few samples. Buoy 46070, found in the western Bering (see map) had a minimum pressure of 28.2 inches of Hg (954 hPa) and gust to nearly 60 kts.

Or Buoy 46035 (to the east) with gusts to 75 knots!

Wave heights at these locations climbed above 35 ft:

The fact that the storm is moving so quickly is preventing the waves from getting catastrophic since big waves requires strong winds, large fetch, and duration to build. Coastal flooding (up to 10 feet storm surge) and blizzard conditions add to the mix. In any case, this will be one of the great storms of the year.

17 comments:

60 hPa in 48 hours? Wow... is that a record pressure drop for 48 hours in an extratropical cyclone? The isobars also look really packed towards the low. This storm covers a huge area, but it seems to have an especially compact pressure gradient near the low.

Sysiphus, the intense low that Dr. Mass refers to is moving north into the Arctic and won't affect the Pac NW. However, this large storm is expected to spawn a new low (which is quite common) over the Aleutians and that will move our way. It will bring western WA rain on Friday. This new low will be well up north in BC/Alberta and only have a central pressure of 992 mb/hPa, so nowhere near the strength of its parent low.

I lived in the region in the 70's and experienced -50 degree temps and 66 knot winds. A short trip outside is an adventure I would not like to repeat. Wishing my friends there all the best for a safe passage.

Is there any way for the NWS and the meteorological society at large to give nomenclature or designation to these extra tropical cyclone and a corresponding level of threat like the Saffir-Simpson scale?

We all know they are extremely dangerous and are in fact worse than many hurricanes. It seems as though the public's perception of the dangers may be decreased because extra tropical depressions or cyclones do not get the public's attention like the term "hurricane".

I have to say 60 hPa in 48 hrs. wow! not a lot of time to warn the public.

This is certainly an impressive storm, with a < 945 hPa central pressure and recorded wind gusts near 90 mph. We occasionally see storms of similar strength impact coastal Washington and B.C. Why is this type of storm so unusual in northwestern Alaska? What factors prevent strong storms like this one from impacting very high latitudes on a more regular basis?

Fascinating Cliff, especially in light of our recent reminiscing about the Columbus Day storm. I suppose the colder waters and air temperatures make large storms like this unusual so far north. But smaller "polar lows" can be very intense with very high winds.